1. Field of the Invention
This invention relates to an ink-drop charging-control device in an ink-jet printer as well as to the application of said device to the control of flow velocity of said ink drops.
2. Description of the Prior Art
The technique of ink-jet writing which utilizes a continuous stream of calibrated droplets delivered by a modulating system involves the need to apply an electrostatic charge to these droplets by means of a suitable electrode. The variable flow of these charged ink drops between plates brought to a high potential results in deflection of drops which is proportional to the charge and makes it possible in conjunction with the displacement of a substrate to obtain printed dot-matrix characters.
Satisfactory performance of the device calls for the introduction of means for controlling the accuracy of charging of ink drops. These means must satisfy a certain number of requirements, mainly in regard to small bulk and high ruggedness of construction. Furthermore, there must be no risk of disadjustment or impairment of the device by the chemically aggressive environment. Finally, in order to ensure efficient operation, the device must not be liable to be disturbed by any electric fields in the immediate vicinity.